package main

import (
	"fmt"
	"time"
)

func byFor() {
	for n := 2; n < 200000; n++ {
		var flag = true
		for i := 2; i < n; i++ {
			if n%i == 0 {
				flag = false
				break
			}
		}
		if flag{
			//fmt.Println("yes", n)
		}
	}
}

func main() {
	start := time.Now().Unix()
	byFor()
	end := time.Now().Unix()
	fmt.Println(end - start)
}
